How to change my desk top picture???

I want a different desk top picture....not one that changes all the time, just an attractive picture that stays on there!!
I have been trying to do it, but cannot get what I like....how do I do it??? What do I go into to choose one??

Go to your desktop, right click (or tap your mousepad with two fingers at once) then choose personalize from the resulting menu. If you choose fill the picture you choose will fill the screen.

Thanks.